Articles and tenses and diagnostic tests

http://www.world-english.org/test.htm get an idea of your level . You should get 1-30 more or less all correct

http://englishdailyworkout.blogspot.com.au/2011/03/present-simple-continuous-exercie-1.html

http://www.perfect-english-grammar.com/past-simple-past-continuous-exercise-1.html

http://www.ego4u.com/en/cram-up/grammar/simpas-paspro/exercises?ex08

http://www.learn4good.com/languages/evrd_grammar/article_ex2.htm

http://www.myenglishpages.com/site_php_files/grammar-exercise-articles.php